1. Field of the Invention
This invention relates to interactive, streaming or broadcast digital video coding, and in particular relates to video coding in compliance with the ITU-T Recommendation H.264.
2. Description of the Related Art
Broadcast television, home entertainment and on-line video streaming have been revolutionized and unified by various video compression technologies. The ISO/IEC MPEG-4 (part 2 visual) and ITU-T H.263 are standards that represent state-of-the-art video compression and decompression technology from circa 2000. In the late 1990's and in parallel with development of H.263 version 3, technical work for a successor to the H.263 video coding standard began within the ITU-T's Video Coding Experts Group (VCEG). In December 2001, the MPEG video group together with VCEG formed a Joint Video Team (JVT) with the goal of leveraging the VCEG work to create a unified video coding standard. The JVT finished work on version 1 of the video coding standard known as ITU-T Recommendation H.264 and ISO/IEC 14496 10 AVC in 2003. It is hereby incorporated by reference.
The new standard surpasses earlier video standards in terms of compression efficiency and resilience to data loss. The improved data compression offers advantages in terms of bandwidth usage. Specifically, given the same video source input, the video pictures reproduced after coding/decoding in compliance with H.264 typically have the same quality as the video pictures reproduced after coding/decoding in compliance with the H.263, MPEG-2 or MPEG-4 (part 2) video coding standards while using approximately half the bandwidth. The many application areas likely to benefit include videoconferencing, video broadcast, streaming and video on mobile devices, telemedicine and distance learning.
Even though H.264 represents a major breakthrough in the video compression technology, there are occasions, especially when coding at low data rates, when the video pictures reproduced after coding/decoding in compliance with the H.264 standard have visual artifacts. Some of those artifacts appear as localized light and dark regions (spanning a few pixels) located along borders or edges of fast-moving objects in the reproduced video pictures. The artifacts appear to make the edges “sparkle.” Each pixel in the “sparkle” artifact is referred to as a “sparkle pixel.” The artifacts appear more readily when the edges of the moving objects are oriented in certain directions. When the transmission bit rate is below a certain rate (dependent on the video source), the artifacts in the reproduced video pictures increase substantially, and may become very distracting.
It is desirable to identify the causes of the sparkling artifacts so as to identify a method and an apparatus to improve the video quality in order to reduce or eliminate the distracting sparkling artifacts in the reconstructed video pictures.